1. Field
The following description relates to a diagnostic imaging apparatus and method.
2. Description of Related Art
Breast sonography is performed to detect masses or lesions that may not be detected by mammography, thereby reducing the need to perform biopsies that may prove to be unnecessary. A mass or lesion may be defined as a suspicious lump of tissues that differs from its surroundings. Women over the age of forty may benefit from breast sonography when mammography detects suspicious findings. Further, breast sonography is recommended for young, skinny women or pregnant women after mammography. The sensitivity of mammography is relatively low for women having dense breasts (for example, Asian women). In recent years, high-frequency probes have been developed for breast sonography. The resolution of sonograms has generally been improved because of the use of the high-frequency probes. In other words, breast sonography has played a significant role, especially for women with dense breasts, as a screening test for breast cancer.
In the meantime, the reading of breast mammograms and the detection of breast masses or lesions are performed according to the Breast Imaging-Reporting and Data System (BI-RDS) guidelines developed by the American College of Radiology (ACR). BI-RAD ultrasound findings include the shape of a lesion detected from a breast sonogram, the boundaries of the lesion, internal echoes, and rear echo shades. Malignant breast lesions are characterized by irregular shapes, lobular shapes, and irregular, rough internal echoes, whereas benign breast lesions are characterized by round shapes, smooth edges, and high, uniform internal echoes. Because cancer cells, unlike normal cells, experience continued growth and infiltrate into other tissues or organs, thereby resulting in lesions with irregular shapes, the shape of a lesion is a factor used to determine malignancy of the lesion. Internal echoes and rear echo shades are additional factors, but may be difficult to determine, especially in sonograms with significant noise or speckles.
The shape of a lesion may be defined as a morphological impression from the whole of a lesion. Lesions may be classified into four shape categories: round/oval, polygonal, lobulated, and irregular. Round/oval lesions are likely to be classified as benign, whereas polygonal, lobulated, or irregular lesions are likely to be classified as malignant. However, the interpretation of the shape of a lesion may be subjective and may thus vary depending on the radiologist. By converting the shape of lesions into numeric data, it is possible to implement a breast ultrasound-based computer-aided diagnosis system.
To properly interpret medical images, shape interpreters may be required. However, shape interpreters may not be able to adequately interpret medical images having significant speckle noise, such as sonograms. In addition, since shape interpreters are limited to the morphological distance and angle between shapes, it may be difficult to properly interpret highly irregular lesion shapes.